U.S. patent application number 09/681822 was filed with the patent office on 2001-11-01 for vehicle headliner and laminate therefor.
Invention is credited to Sandoe, Michael D., Zimmer, Michael G..
Application Number | 20010036788 09/681822 |
Document ID | / |
Family ID | 22111587 |
Filed Date | 2001-11-01 |
United States Patent
Application |
20010036788 |
Kind Code |
A1 |
Sandoe, Michael D. ; et
al. |
November 1, 2001 |
Vehicle headliner and laminate therefor
Abstract
A headliner made from a laminate comprising a core layer
sandwiched between two stiffening layers to form an I-beam
construction that provides the necessary strength for the
headliner. The core layer is preferably a blend of nonwoven fibers
including some fine denier fibers to provide improved sound
absorption properties. The stiffening layers also comprise a blend
of nonwoven fibers. Both the core layer and the stiffening layers
include some binder fibers to bond together the various fibers
within each layer and the layers to each other.
Inventors: |
Sandoe, Michael D.; (Grand
Rapids, MI) ; Zimmer, Michael G.; (Belmont,
MI) |
Correspondence
Address: |
RADER, FISHMAN, GRAUER & MCGARRY PLLC
171 MONROE AVENUE, N.W.
SUITE 600
GRAND RAPIDS
MI
49503
US
|
Family ID: |
22111587 |
Appl. No.: |
09/681822 |
Filed: |
June 11, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09681822 |
Jun 11, 2001 |
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09239112 |
Jan 28, 1999 |
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60073077 |
Jan 30, 1998 |
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Current U.S.
Class: |
442/389 ;
442/340; 442/344; 442/351; 442/361; 442/381 |
Current CPC
Class: |
Y10T 442/659 20150401;
B32B 2262/0261 20130101; Y10T 442/637 20150401; Y10T 442/619
20150401; B32B 2605/08 20130101; D04H 1/559 20130101; Y10T 442/622
20150401; B32B 2262/0253 20130101; B32B 5/26 20130101; Y10T 442/668
20150401; Y10T 442/626 20150401; B32B 7/12 20130101; B60R 13/0225
20130101; B32B 2262/0276 20130101; Y10T 442/614 20150401; Y10S
428/903 20130101; Y10T 442/671 20150401 |
Class at
Publication: |
442/389 ;
442/381; 442/340; 442/361; 442/344; 442/351 |
International
Class: |
B32B 005/06; D04H
001/00; D04H 003/00; D04H 005/00 |
Claims
1. A laminate for use in making a thermoformed article, the
laminate comprising: first and second strengthening layers and a
core layer disposed between the strengthening layers, with the
strengthening layers providing the predominate flexural rigidity
for the laminate and the core layer providing the predominate sound
absorption for the laminate; the core layer comprises a batt of
nonwoven thermoplastic fibers comprising: 20-50% fine fibers with a
denier in the range of 0.8-3.0; and 10-50% binder fibers for at
least binding together the fine fibers; and regular fibers having
denier in the range of 4.0-15 denier; the first and second
strengthening layers comprise a batt of nonwoven polymeric fibers
comprising: regular fibers having a denier greater than the fine
fibers of the core layer and in an amount to provide flexural
rigidity to the laminate.
2. A laminate according to claim 1 wherein the thermoplastic fibers
include polyester, polyolefins, and nylon.
3. A laminate according to claim 2 wherein the polyester fibers
include bicomponent fibers.
4. A laminate according to claim 3 wherein the binder fibers have a
denier in the range of 0.8-200.
5. A laminate according to claim 4 wherein the binder fibers have a
denier in the range of 6-25.
6. A laminate according to claim 1 wherein the core layer batt has
a basis weight in the range of 6-12 ounces/yd.sup.2.
7. A laminate according to claim 6 wherein the unmolded core layer
batt has a thickness of 0.5-1.0 inches.
8. A laminate according to claim 1 wherein the core layer batt has
a basis weight of 6-24 ounces/yd.sup.2.
9. A laminate according to claim 8 wherein the unmolded core layer
batt has a thickness of 0.5-2.0 inches.
10. A laminate according to claim 1 wherein the binder fibers
comprise bicomponent fibers.
11. A laminate according to claim 1 wherein the binder fibers
comprise low melting point fibers.
12. A laminate according to claim 1 wherein the core layer batt
comprises 35-45% by weight fine fibers having a denier of 0.8-1.2,
20-30% by weight fibers having a denier of 10-15, and the binder
fibers comprise 30-40% by weight bicomponent fibers having a denier
of 4-15.
13. A laminate according to claim 12 wherein the core layer batt
comprises about 40% by weight fine fibers having a denier of about
1.0, about 25% by weight regular fibers having a denier of about
15, and about 35% by weight bicomponent fibers having a denier of
about 5.
14. A laminate according to claim 12, and further comprising a
first and second web adhesive layer, the first web adhesive layer
is disposed between the core layer and the first strengthening
layer, and the second web adhesive is disposed between the core
layer and the second strengthening layer, whereby the web adhesives
enhance the bonding between the strengthening layers and the core
layer.
15. A laminate according to claim 14 wherein the web adhesive is a
sheet of nonwoven polyester fibers.
16. A laminate according to claim 1, and further comprising a first
and second web adhesive layer, the first web adhesive layer is
disposed between the core layer and the first strengthening layer,
and the second web adhesive is disposed between the core layer and
the second strengthening layer, whereby the web adhesives enhance
the bonding between the strengthening layers and the core
layer.
17. A laminate according to claim 16, and further comprising a
cover material bonded to the lower surface of the second
strengthening layer.
18. A laminate according to claim 1 wherein the strengthening layer
batts comprise: 50-100% by weight polymeric fibers with a denier of
0.8-200, and 0-50% by weight binder materials.
19. A laminate according to claim 18 wherein the binder materials
are binder fibers.
20. A laminate according to claim 18 wherein the polymeric fibers
have a denier of 3-25.
21. A laminate according to claim 20 wherein the strengthening
layer batts have a basis weight of 3-24 ounces/yd.sup.2.
22. A laminate according to claim 21 wherein the unmolded
strengthening layer batts have a thickness of 0.1-1.0 inches.
23. A laminate according to claim 22 wherein the binder materials
incude a thermosetting resin.
24. A laminate according to claim 23 wherein the thermosetting
resin is a powder which is present in an amount up to 20% by weight
in the strengthening layers.
25. A laminate according to claim 1, wherein the core layer regular
fibers from the balance of the fiber in the core layer.
26. A laminate according to claim 1, wherein the strengthening
layers have a greater density than the core layer.
27. A laminate according to claim 26, wherein the strengthening
layers are thinner than the core layer.
28. A laminate according to claim 27, wherein the core layer has a
greater resistivity than the strengthening layers.
29. A laminate according to claim 1, wherein each strengthening
layer comprises less than 20% fine fibers.
30. A laminate according to claim 29, wherein the core layer
comprises at least 25% fine fibers.
31. A laminate according to claim 1, wherein the percentage of fine
fibers in each of the strengthening layers is not greater than half
the percentage of fine fibers in the core layer and the fine fibers
of each strengthening layer not exceeding 20%.
32. A laminate according to claim 1 wherein the denier of the core
layer fine fibers is below 2.7.
33. A headliner for a vehicle comprising: first and second
strengthening layers and a core layer disposed between the
strengthening layers, with the strengthening layers providing the
predominate flexural rigidity for the headliner to prevent sagging
and the core layer providing the predominate sound absorption for
the headliner; the core layer comprises a batt of nonwoven
thermoplastic fibers comprising: 20-50% fine fibers with a less
than 2.7 for absorbing sound; and 10-50% binder fibers for at least
binding together the fine fibers; and the first and second
strengthening layers comprise a batt of nonwoven polymeric fibers
comprising: regular fibers having a denier greater than the fine
fibers of the core layer and of an amount to provide flexural
rigidity to the headliner.
34. A headliner according to claim 33 wherein the thermoplastic
fibers include polyester, polyolefins, and nylon.
35. A headliner according to claim 34 wherein the polyester fibers
include bicomponent fibers.
36. A headliner according to claim 35 wherein the binder fibers
have a denier in the range of 0.8-200.
37. A headliner according to claim 36 wherein the binder fibers
have a denier in the range of 6-25.
38. A headliner according to claim 37 wherein the core layer batt
has a basis weight of 6-12 ounces/yd.sup.2.
39. A headliner according to claim 38 wherein the core layer batt
has a molded thickness of 0.1-1.3 inches.
40. A headliner according to claim 36 wherein the core layer batt
has a basis weight of 6-24 ounces/yd.sup.2.
41. A headliner according to claim 40 wherein the core layer batt
has an molded thickness of 0.1-1.5 inches.
42. A headliner according to claim 33 wherein the binder material
comprises a thermosetting resin.
43. A headliner according to claim 42 wherein the thermosetting
resin comprises up to 20% of the core layer.
44. A headliner according to claim 33 wherein the core layer batt
comprises 35-45% fine fibers having a denier of 0.8-1.2, 20-30%
regular fibers having a denier of 10-15, and the binder materials
comprise 30-40% bicomponent fibers having a denier of 4-15.
45. A headliner according to claim 44 wherein the core layer batt
comprises about 40% fine fibers having a denier of about 1.0, about
25% regular fibers having a denier of about 15, and about 35%
bicomponent fibers having a denier of about 5.
46. A headliner according to claim 45, and further comprising a
first and second web adhesive layer, the first web adhesive layer
is disposed between the core layer and the first strengthening
layer, and the second web adhesive layer is disposed between the
core layer and the second strengthening layer, whereby the web
adhesives enhance the bonding between the strengthening layers and
the core layer.
47. A headliner according to claim 46 wherein the web adhesive is a
sheet of nonwoven polyester fibers.
48. A headliner according to claim 46 wherein the strengthening
layer batts comprise: 50-100% by weight polymeric fibers with a
denier of 0.8-200, and 0-50% by weight binder materials.
49. The headliner according to claim 48, wherein the core layer
regular fibers have a denier between 4-15.
50. The headliner according to claim 48, wherein the polymeric
fibers have a denier of 3-25.
51. The headliner according to claim 50, wherein the polymeric
fibers are thermoplastic fibers.
52. A laminate for use in making a thermoformed article, the
laminate comprising: first and second strengthening layers and a
core layer disposed between the strengthening layers, with the
strengthening layers providing the predominate flexural rigidity
for the laminate and the core layer providing the predominate sound
absorption for the laminate; the core layer comprises a batt of
nonwoven thermoplastic fibers comprising: 20-50% fine fibers with a
denier in the range of approximately 0.8-3.0 denier for absorbing
sound; 10-50% binder fibers for at least binding together the fine
fibers; and the balance of regular fibers having a denier in the
range of about 4.0-15.0; the first and second strengthening layers
comprising a batt of nonwoven polymeric fibers and have a density
greater than the core layer.
53. The laminate according to claim 52, wherein the polymeric
fibers comprise regular fibers having a denier greater than the
fine fibers of the core layer and of an amount to provide
structural rigidity to the laminate.
54. The laminate according to claim 53, wherein the strengthening
layers are thinner than the core layer.
55. The laminate according to claim 54, wherein the core layer has
a greater resistivity than the strengthening layers.
56. The laminate according to claim 55, wherein each strengthening
layer comprises less than 20% fine fibers.
57. The laminate according to claim 56, wherein the core layer
comprises at least 25% fine fibers.
58. The laminate according to claim 57, wherein the percentage of
fine fibers in each of the strengthening layers is not greater than
half the percentage of fine fibers in the core layer and the fine
fibers of each strengthening layer not exceeding 20%.
59. A laminate for use in making a thermoformed article, the
laminate comprising: first and second strengthening layers and a
core layer disposed between the strengthening layers, with the
strengthening layers providing the predominate flexural rigidity
for the laminate and the core layer providing the predominate sound
absorption for the laminate; the core layer comprises a batt of
nonwoven thermoplastic fibers comprising: 20-50% fine fibers with a
denier in the range of approximately 0.8-3.0 denier for absorbing
sound; and 10-50% binder fibers for at least binding together the
fine fibers; and the first and second strengthening layers comprise
a batt of nonwoven polymeric fibers and the core layer has a
resistivity greater than at least one of the first and second
strengthening layers.
60. The laminate according to claim 59, wherein the first and
second strengthening layers comprise a batt of nonwoven polymeric
fibers comprising regular fibers having a denier greater than the
fine fibers of the core layer and of an amount to provide
structural rigidity to the laminate.
61. The laminate according to claim 59, wherein the strengthening
layers are thinner than the core layer.
62. The laminate according to claim 59, wherein each strengthening
layer comprises less than 20% fine fibers.
63. The laminate according to claim 62, wherein the core layer
comprises at least 25% fine fibers.
64. The laminate according to claim 58, wherein the percentage of
fine fibers in each of the strengthening layers is not greater than
half the percentage of fine fibers in the core layer and the fine
fibers of each strengthening layer not exceeding 20%.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation in part of U.S. patent
application Ser. No. 09/239,112, filed Jan. 28, 1999, which claims
priority on U.S. provisional patent application No. 60/073077,
filed Jan. 30,1998.
BACKGROUND OF INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to vehicle headliners. In one of its
aspects, the invention relates to a vehicle headliner. In another
of its aspects, the invention relates to a laminate construction
for a vehicle headliner that optimizes formability, sound absorbing
properties and structural integrity of the vehicle headliner.
[0004] 2. Description of the Related Art
[0005] Vehicle headliners on the interior of an automobile are a
decorative panel which separates the passenger compartment from the
sheet metal forming the roof of the vehicle. The vehicle headliners
absorb sounds from within the passenger compartment as well as
sounds originating outside the passenger compartment. Soft fibrous
materials are typically used this function, but must be stiffened
to give the headliners sufficient structural rigidity to avoid sag
in service under all types of service conditions. It is further
important that the overall thickness of the headliner be relatively
small to maximize headroom within the vehicle compartment. In many
applications, it is expected that the headliner will be
sufficiently strong to support its own weight.
[0006] Previous commercial headliners have been made with
fiberglass batting which is impregnated with a thermosetting resin
for rigidity. Some of these panels have been relatively brittle and
have failed when installed into vehicles. Further, glass fibers can
cause handling problems. These headliners are typically not
recyclable.
[0007] The required headliner properties of sound absorption,
rigidity, and minimum thickness often conflict with each other and
compromises must be made to reach optimum properties. Sound
absorption is most easily obtained by making the headliner from a
low density material that absorbs the sound waves as they enter the
headliner and minimizes reflection of the sound waves as would more
dense materials. In general, the greater the thickness of the
low-density material, the greater the sound absorption but, thicker
materials have a greater tendency to sag and adversely affect
headroom. Generally, dense materials are used to provide the
headliner with the necessary structural strength and rigidity for
supporting its own weight and possibly mounting components to the
headliner. More dense materials, in general, tend to reflect sound
and thus, negatively impact sound absorption.
[0008] Some prior headliners have attempted to resolve the conflict
between the sound absorbing and structural rigidity requirements
for the headliner by making the headliner from a laminate of
various materials, wherein some of the materials provide the
structural rigidity and other of the materials provide the sound
absorbing properties. One approach is to use a relatively
low-density sound absorbing material sandwiched between two layers
of reinforcing material. One of the reinforcing material layers has
mounted thereto a decorative cover that forms the ceiling of the
passenger compartment of the vehicle. An example of this structure,
which is known as an I-beam construction, is disclosed in U.S. Pat.
No. 4,828,910 to Haussling, issued May 9, 1989.
[0009] Most prior I-beam constructions use a thermosetting resin to
bind together the various layers of the laminate. The resin is
normally sprayed in liquid form on at least one of the abutting
surfaces of the various layers. In general, the thermosetting resin
negatively impacts the sound absorbing characteristics of the
laminate because the resin can fill the interstitial spaces between
the fibers in the laminate and thereby increase the reflectance of
the sound waves instead of absorbing the sound waves. Thermosetting
resins also make it more difficult if not impossible to recycle the
laminate, which is an important characteristic and often a
requirement of most components used in contemporary vehicle
construction.
[0010] The U.S. patent to Weinle, U.S. Pat. No. 4,840,832, issued
Jun. 20, 1989, discloses a headliner construction of a bicomponent
fiber wherein the fibers are bonded together at their crossing
points. The headliner is said to be so highly deformable and
resilient that it can be bent or flexed nearly double to facilitate
installation in an automobile side window and subsequently will
resiliently recover to its original molded shape. Actual
embodiments of these headliners have not had sufficient rigidity to
avoid sag when subjected to elevated temperatures normally
experienced in vehicles except when the mass and density of the
headliners is very high, thereby negatively impacting vehicle fuel
efficiency.
[0011] U.S. Pat. No. 6,066,388 to Van Kerrebrouck discloses a
non-woven laminate comprising two outer fiber layers and at least
one inner fiber layer having a different composition from that of
the outer layers. The inner layer contains constructive fibers
having a thickness of 3-100 dtex in combination with 20-100%
binding fibers. The outer layers comprise constructive fibers
having a thickness of 0.5-28 dtex in combination with 40-100%
binding fibers. The thickness of the constructive fibers of the
outer layers are thinner than the constructive fibers of the inner
layer.
SUMMARY OF INVENTION
[0012] According to the invention, a laminate comprises first and
second strengthening outer layers and a core layer between the
strengthening layers. Each of the outer layers comprises a batt of
nonwoven polymeric fibers. The outer layer provides the predominate
flexural rigidity for the laminate and the core layer provides the
predominate sound absorption for the laminate. The core layer batt
preferably comprises 20-50% fine fibers, preferably with a denier
less than 2.7, 10-50% binder fibers and the balance regular fibers
with a denier in the range of 4.0-15.0. The thermoplastic fibers
can include polyester, polyolefin, and nylon.
[0013] The polyester fibers preferably include bicomponent fibers,
such as a PET sheath-core bicomponent fiber. The core layer
comprises regular fibers having a denier greater than the fine
fibers of the core layer and in an amount to provide flexural
rigidity to the laminate.
[0014] The binder fibers preferably have a denier in the range of
0.8-200, with a preferred range of 3-25 denier. The core layer batt
has a basis weight in the range of 6-24 ounces/yd.sup.z, with a
preferred range of 6-12 ounces/yd.sup.z. The core layer batt has a
thickness of 0.5-2.0 inches, with a preferred thickness of 0.5-1.0
inches.
[0015] The laminate can further include first and second web
adhesive layers that are positioned between each of the outer
layers and the core layer. The web adhesive layers enhance the
bonding between the outer layers and the core layer. Preferably,
the web adhesive layer is a sheet of nonwoven polyester fibers.
[0016] The outer layers preferably comprise 50-100% by weight of
thermoplastic fibers with a denier of 0.8-200 and 0-50% by weight
of binder materials. The binder materials can include binder
fibers. Additionally, the binder materials can include a
thermosetting resin, which is preferably a thermosetting powder
that is present in an amount up to 20% by weight of the outer
layers.
[0017] The strengthening layers are preferably thinner than the
core layer. The core layer has a greater resistivity than the
strengthening layers. Preferably, each strengthening layer
comprises less than 20% fine fibers and the core layer comprises at
least 25% fine fibers. The percentage of fine fibers in each of the
strengthening layers is preferably not greater than half the
percentage of fine fibers in the core layer and the fine fibers of
each strengthening layer not exceeding 20%.
[0018] Headliners made according to the invention have better sound
absorbing properties and yet maintain the required structural
rigidity properties, while minimizing thickness and density to
maximize vehicle headroom and fuel efficiency, and are recyclable.
Further, the headliners according to the invention are free of
fiberglass and are flexible enough to avoid failure during
installation and are less irritable to workers during handling,
while satisfying requirements for low density and dimensional
stability.
[0019] In yet another embodiment, the invention relates to a
laminate comprising first and second strengthening layers and an
intermediate core layer. Each of the strengthening layers comprises
a batt of nonwoven polymeric fibers. The strengthening layers
provide flexural rigidity for the laminate. The core layer provides
sound absorption for the laminate and includes a batt of nonwoven
thermoplastic fibers. The core layer batt preferably comprises
20-50% fine fibers with a denier in the range of 0.8-3.0, 10-50%
binder fibers and the balance regular fibers with a denier in the
range of 4.0-15.0, and. The first and second strengthening layers
each comprise a batt of nonwoven polymeric fibers and have a
density greater than the core layer.
[0020] The strengthening layers are preferably thinner than the
core layer. The core layer has a greater resistivity than the
strengthening layers. Preferably, each strengthening layer
comprises less than 20% fine fibers and the core layer comprises at
least 25% fine fibers. The percentage of fine fibers in each of the
strengthening layers is preferably not greater than half the
percentage of fine fibers in the core layer and the fine fibers of
each strengthening layer not exceeding 20%.
[0021] In another embodiment, the invention relates to a laminate
comprising first and second strengthening layers and an
intermediate core layer. Each of the strengthening layers comprises
a batt of nonwoven polymeric fibers. The strengthening layers
provide the predominate flexural rigidity for the laminate. The
laminate further comprises a core layer disposed between the
strengthening layers. The core layer provides sound absorption for
the laminate. The core layer includes a batt of nonwoven
thermoplastic fibers. The core layer batt preferably comprises
20-50% fine fibers with a denier in the range of 0.8-3.0, 10-50%
binder fibers, and the balance regular fibers with a denier in the
range of 4.0-15.0. The first and second strengthening layers each
comprise a batt of nonwoven polymeric fibers and the core layer has
a resistivity greater than at least one of the first and second
strengthening layers.
BRIEF DESCRIPTION OF DRAWINGS
[0022] The invention will now be described with reference to the
drawings in which:
[0023] FIG. 1 illustrates a vehicle headliner according to the
invention; and
[0024] FIG. 2 is a cross-section taken along the lines 2-2 of FIG.
1 illustrating the laminate construction of the vehicle headliner
according to the invention.
DETAILED DESCRIPTION
[0025] -6-FIG. 1 illustrates a headliner 10 according to the
invention. The headliner 10 has improved sound absorbing properties
in combination with structural rigidity, while maintaining a
relatively thin cross-section. The headliner 10 accomplishes the
sound absorbing function while maintaining sufficient structural
rigidity to avoid bowing or sagging when exposed to heat and is
capable of supporting at least its own weight. The headliner 10
accomplishes this result without undue thickness, which would
undesirably reduce the available headroom in the passenger
compartment of the vehicle and without undue density which would
decrease vehicle fuel efficiency.
[0026] As best seen in FIG. 2, the headliner 10 comprises a
laminate construction including a core layer 12 sandwiched between
two stiffening layers 14 and 16. A decorative cover 18 is applied
to the stiffening layer (in this case stiffening layer 16) that
faces the interior of the vehicle. The decorative fabric covering
18 defines the ceiling of the passenger compartment when the
headliner is installed. Preferably, layers of web adhesive 20, 22
are disposed between each stiffening layer 14, 16 and the core
layer 12 to enhance the bond therebetween.
[0027] The core layer 12 comprises a batt of a blend of nonwoven
fibers, including fine denier fibers, regular denier fibers, and
binder materials, which preferably includes binder fibers with a
lower melting point fiber component. The denier of the fibers in
the core layer can vary over a wide range but generally will be in
the range of 0.8 to 200, denier, and preferably in the range of 0.8
to 15 denier. Preferably the core layer contains 20-50% by weight
(all composition percentages are by weight unless otherwise noted)
of fine fibers in the range of approximately 0.8 to 3 denier, 0 of
fibers in the range of approximately 4 to 15 denier, and 10-50%
binder fibers. At least some of the binder fibers can be the fine
denier fibers and the regular denier fibers, especially if either
of these fibers is a bicomponent fiber having a high melting point
core and a low melting point sheath, such as is found in U.S. Pat.
No. 4,195,112 to Sheard. The binder fibers can also be a blend of
high and low melting point thermoplastic fibers.
[0028] The core layer batt fiber blend with the fine denier fibers
has excellent sound absorption properties while maintaining a low
mass. The thickness of the core layer ranges from 0.5 to 2", and is
preferably from 0.5 to 1". The basis weight of the core layer 12
can range from 6 to 24 ounces/yd.sup.2 and is preferably in the
range of 6 to 12 ounces/yd.sup.2 . The fibers in the core layer can
be a variety of synthetic and natural fiber and are preferably
thermoplastic fibers, including polyester, polypropylene, nylon,
and copolymeric bicomponent fiber of polyester.
[0029] The binder fibers can be mixed with the fine and regular
denier fibers to provide the core layer 12 with dimensional
stability when exposed to high and/or low temperatures, humidity,
or mechanical strain. Preferably the binder fibers are fully or
partially crystallized bicomponent or staple fibers, such as
Hoechstj58, Wellman T0196, or Unitika 7080 polyester or polyolefin
bicomponent fibers. The bicomponent fibers are formed a low melting
point sheath in combination with a high melting point core
construction. The low melting point material will soften and bond
with other fibers in the core layer 12 to bond the core layer
fibers at their cross over points, leaving open the interstitial
spaces between the fibers, permitting the sound waves to pass into
the core for absorption.
[0030] The stiffening layers 14 and 16 can comprise a batt of
similar or dissimilar fiber blends of nonwoven fibers having a
denier in the range of 0.8 to 200, and preferably in the range of 3
to 25 denier. The stiffening layers 14 and 16 are generally from
0.1 to 1.0" thick, preferably are from 0.2 to 0.5" thick, and
contain 20-50% binder material. The binder material can include
binder fibers as well as other materials, such as resins. The
stiffening layers have a basis weight in the range of 3 to 24
ounces/yd.sup.2, and preferably in the range from 6 to 18
ounces/yd.sup.2.
[0031] The fibers comprising the stiffening layers 14 and 16 are
preferably any thermoplastic plastic fiber, such as polyester,
polypropylene, nylon, and copolymer bicomponent fiber of polyester.
In essence, the fibers of the stiffening layers 14, 16 can be the
same fibers as the core, but preferably do not include the fine
fibers because of their relative reduced strength characteristic.
But, fine fibers can be included in the stiffening layers as long
as the necessary strength is achieved.
[0032] Although it is not preferred, it is within the scope of the
invention for the stiffening layers to include thermosetting resins
but care must be taken to make sure the resin does not block the
interstitial spaces between the fibers to a degree that the
beneficial sound absorbing properties of the laminate are lost. The
clogging of the interstitial spaces increases the batts sound
reflection characteristics which prevents the sound waves from
entering the core where they can be absorbed. Preferably, a
thermosetting powder is used instead of a liquid resin. The
thermosetting powder can be applied to the fibers without clogging
the interstitial spaces between the fibers as much as a liquid
thermosetting resin that is sprayed onto the fibers. The
thermosetting binder can include phenolic, epoxy, or urethane
binders, for example. If a thermosetting binder material is used,
it is preferred that it does not comprise more than 20% of the
strengthening layer.
[0033] The decorative fabric covering 18 can be made of any
suitable fabric conventionally used for headliners and is not a
part of the invention. Also, depending on the characteristics of
the stiffening layer 16, it is possible to forego the decorative
fabric covering 18 if the characteristics of the stiffening layer
16 are aesthetically satisfactory. The decorative covering material
18 preferably comprises urethane foam-backed knit fabrics, or
needle punched fabrics.
[0034] The web adhesive layers 20, 22 are preferably a sheet of
nonwoven thermoplastic fibers having interstitial spaces between
the fibers. The fibers are preferably co-polyester. The web
adhesive is advantageous or the prior techniques, such as a liquid
adhesive or liquid resin, for bonding together the laminate layers
because the web adhesive does not fill in the interstitial spaces
between the fibers at the interface between the laminate layers but
forms a fiber to fiber bond, thereby increasing the bond without
substantially decreasing the sound reflectance of the laminate. A
suitable web adhesive is PE2900 manufactured by Spunfab, Ltd. Of
Cuyahoga Falls, Ohio.
[0035] In a preferred embodiment, the core layer 12 has a fiber
composition of 40% 0.9 denier 11/2 inch polyetheylene teraphalate
(PET) fibers, 35% 4 denier 2 inch PET bicomponent fibers, and 25%
15 denier 2 inch PET fibers. The core layer has a nominal thickness
of approximately 1-inch and a basis weight of 12 oz/yd.sup.2. Each
of the stiffening layers has a fiber composition of 40% 4 denier 2
inch PET heat resistant sheath core bicomponent fibers and 60% 15
denier 2 inch PET fibers. The stiffening layers have a nominal
thickness of 0.30 inches and a basis weight of 12 oz/yd.sup.2. The
web adhesive layer is a thermoplastic PET web adhesive (Spunfab
PE2900).
[0036] The headliner 10 is preferably manufactured by
simultaneously thermoforming the core layer 12, stiffening layers
14 and 16, and the decorative fabric covering 18 and web adhesive
layers 20, 22 if used. The thermoforming can include preheating of
the materials using radiant, conductive or convective sources
followed by molding in cold tools, or by molding in thermally
regulated warm or hot tools.
[0037] During molding of the headliner, the mold is closed and
cooled to a temperature less than the melting point of the binder
materials to thereby set the thermopistic binder materials and form
the fiber to fiber bonds at the fiber cross over points.
Alternatively, cool laminate may be presented to a thermally
regulated warm or hot tool to thereby soften the binder materials
and form the fiber to fiber bonds. The laminate is compressed
(either before or after the softening of the binder material) to
form the desired contoured surface of the headliner and, in many
cases, structural ribs in headliner. The amount of heating and
compression will depend on the materials used in the laminate and
the desired properties of the final headliner. After heating and
compression, the general overall thickness of the headliner is
about 20 mm and the structural ribs have a thickness of about 2
mm.
[0038] If no web adhesive or other adhesive is used between the
layers, the layers can be self-bonded together under the influence
of heat pressure of the molding operation which causes at the
interface between the layers to bond at the fiber cross over
points. If the decorative fabric covering 18 is used, it can be
molded to a previously formed substrate of the core layer 12 and
stiffening layers 14 and 16 as a secondary step. Advantageously,
the materials can be molded to variable thickness to accommodate
design requirements within a range of 0.1 to 1.5" thick.
[0039] The advantages of the headliner 10 according to the
invention are best seen by reviewing various molded samples of
laminates according to the invention and compared against prior
headliner constructions.
[0040] Table 1 illustrates the increased modulus of elasticity
obtained from the I-beam construction as compared to a single layer
construction for various laminate thicknesses. Sample 1 is a
construction according to the invention. It has an overall basis
weight of 24 ounces/yd.sup.2. The core layer has a basis weight of
12 ounces/yd.sup.2 and a fiber blend of 25% Wellman 15 denier PET
staple fibers (Wellman 15), 25% Wellman 6 denier PET staple fibers
(Wellman 6), and 50% Unitika 4 denier PET sheath-core bicomponent
type 7080 fibers (Unitika 4). The first and second stiffening
layers both have a basis weight of 6 ounces/yd.sup.2 and comprise a
fiber blend of 50% Wellman 6 and 50% Unitika 4. The single layer
construction (Single Layer 1) has an overall basis weight of 24
ounces/yd.sup.2 and comprises a blend of fibers identical to the
core layer of Sample 1. The Sample 1 and Single Layer 1 laminates
were made by first pre-heating each laminate for 2-3 minutes by
exposing the top and bottom of each laminate with an infrared
heating element having a surface temperature of
650.degree.-850.degree. F. The pre-heated laminates were then
placed in a flat mold under 1-2 psi where they cooled for
approximately one minute. All of the laminates subsequently
described herein were made in the same manner. Table 1 shows the
modulus of elasticity according to ASTM D790 for Sample 1 and
Single Layer 1, each having identical basis weight and thickness.
From table 1 it can be seen that the I-beam construction of Sample
1 provides increased modulus of elasticity when compared to Single
Layer 1 for a given thickness.
1TABLE 1 Comparison of Modulus of Elasticity between laminate
Construction and a single layer Construction at required Thickness
[t7] Thickness Modulus of Elasticity Sample (inches) (psi; ASTM
D790) Sample 1 .12 16,800 Single Layer 1 .12 14,500 Sample 1 .45
1,700 Single Layer 1 .45 1,000 Sample 1 .68 680 Single Layer 1 .68
205
[0041] Table 2 illustrates the sound absorption benefits per ASTM
C423 testing of the core layer 12 comprised of a fiber blend
including fine denier fibers (Sample 2) as compared to a currently
manufactured standard substrate (Standard Substrate) which do not
have a fiber blend that includes fine denier fibers.
[0042] Sample 2 is only a core layer 12 having a basis weight of 12
ounces/yd.sup.2 and a fiber blend of 20% Wellman 15,10% Wellman
4.75 denier PET sheath-core bicomponent type 712P fibers (Wellman
4.75), and 70% Wellman 1.2 denier PET staple fibers (Wellman
1.2).
[0043] The Standard Substrate weighs 18 ounces/yd.sup.2 and has a
fiber blend of 15% Wellman 4.75, and 85% Talon 6 denier mixed
reclaimed synthetic fibers (Talon 6). Sample 2 has a thickness of
0.94" and the Standard Substrate has a thickness of 0.95
inches.
2TABLE 2 Comparison of Sound Absorption Properties Between a Core
Layer with Fine Denier Fibers and a Heavier Standard Substrate at
an equal Thickness [t1] Percent Sound Absorption at Various
Frequencies Sample 250 HZ 500 HZ 1000 HZ 2000 HZ 4000 HZ Sample 2
26 52 73 81 88 Standard 22 48 72 93 91 Substrate
[0044] From table 2 it can be seen that even though Sample 2 with
the fine fibers has a two-thirds the mass to absorb sound it still
absorbs a similar percentage of sound over the tested range to that
of the Standard Substrate, and has a slightly better performance at
the lower frequencies and slightly worse performance at the higher
frequencies. Therefore, the core layer according to the invention,
as illustrated by Sample 2, provides generally better sound
absorption in the lower frequency range for a given thickness, but
at a reduced weight. The reduced weight places less load on the
headliner and helps to reduce the vehicle weight, which are advance
over prior headliner constructions.
[0045] Table 3 illustrates the ASTM C423 sound absorbing properties
of a laminate with I-beam construction comprising the core layer 12
and the stiffening layers 14 and 16 (Sample 3) as compared to a
single layer (Single Layer 2) of sound absorbing material at a
given basis weight and thickness. Sample 3 comprises a core layer
weighing 12 ounces/yd.sup.2 with a fiber blend of 50% Wellman 6,
35% Wellman 0.9 denier PET staple fibers (Wellman 0.9), and 15%
Wellman 4.75. Sample 3 also includes stiffening layers 14 and 16
weighing 12 ounces/yd.sup.2 and comprised of 20% Wellman 15, 50%
Wellman 6, and 30% Unitika 4. Single Layer 2 is actually three
layers of the same material. Each layer weighs 12 ounces/yd.sup.2
with a fiber blend of 100% Talon 6 denier mixed reclaimed synthetic
fibers (Talon 6). The Talon 6 material has denier in the range of
3-15 denier. The average denier is 6. The overall basis weight is
of Single Layer 2 is 36 ounces/yd.sup.2.
[0046] Sample 3 and Single Layer 2 both have a basis weight of 36
ounces/yd.sup.2 and are similar in thickness with Sample 3 having a
thickness of 0.47" and the single layer having a thickness of
0.50". As can be seen from table 3, the laminate of Sample 3
according to the invention has significantly better sound absorbing
properties throughout the entire tested range. Therefore, for a
given weight and thickness, a laminate made according to the
invention provides significantly better sound absorbing properties
than previous single layer constructions.
3TABLE 3 Comparison of Sound Absorption Properties Between a
Laminate Construction and a Single Layer at equal Basis and
Generally equal Thickness [t2] Percent Sound Absorption at Various
Frequencies Sample 250 HZ 500 HZ 1000 HZ 2000 HZ 4000 HZ Sample 3 9
28 55 78 89 Single 7 15 40 59 83 Layer 2
[0047] Table 4 illustrates the structural rigidity of previous
laminate constructions and laminate constructions according to the
invention by comparing the sag of the materials at approximately
equal thicknesses with varying basis weights and binder material
percentages.
[0048] The cantilevered beam sag test consisted of taking a
3".times.12" section from each flat molded sample and clamping the
first two inches of the 12" length. The cantilevered beam was
exposed to 185.degree. F. for 24 hours under its own weight. The
amount of sag was measured by the deflection of the extreme end of
the cantilever beam sample.
[0049] Samples 4, 9 and 14 according to the invention all comprise
a core layer 12 having a fiber blend of 30% Wellman 15, 45% Wellman
0.9, and 25% Unitika 4, and a basis weight of 12 ounces/yd.sup.2.
Additionally, the stiffening layers 14 and 16 have a basis weight
of 12 ounces/yd.sup.2 and are a blend of 50% Wellman 15 and 50%
Wellman 4.75. Overall, the core layer 12 comprises 8% heat
resistant thermoplastic binder material.
[0050] Samples 5, 10, and 15 have an overall basis weight of 36
ounces/yd.sup.2. The core layer 12 has a basis weight of 12
ounces/yd.sup.2 and a fiber blend of 30% Wellman 6, 45% Wellman 0.9
and 25% Unitika 4. The stiffening layers 14 and 16 each have a
basis weight of 12 ounces/yd.sup.2 and a fiber blend of 50% Wellman
15, 25% Unitika 4 and 25% polyester spunbond scrim. Overall, the
core layer 12 comprises 25% heat resistant thermoplastic binder
material.
[0051] Samples 6, 11, and 16 have an overall basis weight of 36
ounces/yd.sup.2 and an overall composition comprising 33% heat
resistant thermoplastic binder material. The core layer 12 has a
basis weight of 12 ounces/yd.sup.2 and a fiber blend of 67%
Martin-Color-Fl 200 denier PET staple (Martin) and 33% BF Goodrich
polyvinyl latex type 352 (BF Goodrich). The stiffening layers 14
and 16 each have a basis weight of 12 ounces/yd.sup.2 and a fiber
blend of 50% Wellman 15 and 50% Unitika 4.
4TABLE 4 Comparison of Laminate Sag with and without Binder Fibers
at Approximately equal Thickness Heat Resistant Thermoplastic
Thickness Binder % Sag Sample Basis Weight (oz/yd.sup.2) (inches)
(Percentage) (inches) [t3] Prior 1 52 .18 0 .35 Sample 4 36 .18 8
3.94 Sample 5 36 .20 25 2.8 Sample 6 36 .19 33 1.65 Sample 7 36 .20
42 1.14 Sample 8 36 .12 50 .59 [t4] Prior 2 52 .49 0 1.85 Sample 9
36 .38 8 3.46 Sample 10 36 .46 25 3.11 Sample 11 36 .44 33 1.46
Sample 12 36 .46 42 1.42 Sample 13 36 .47 50 .67 Prior 3 38 .82 0
1.91 Sample 14 36 .57 8 3.51 Sample 15 36 .62 25 2.71 Sample 16 36
.60 33 1.69 Sample 17 36 .59 42 1.57 Sample 18 36 .68 50 0.39
[0052] Samples 7, 12, and 17 have an overall basis weight of 36
ounces/yd.sup.2 and an overall composition of 42% heat resistant
thermoplastic binder material. The core layer 12 has a basis weight
of 12 ounces/yd.sup.2 and a fiber blend of 30% Wellman 6, 45%
Wellman 0.9, and 25% Unitika 4. The stiffening layers 14 and 16
each have an overall basis weight of 12 ounces/yd.sup.2 and a fiber
blend of 50% Wellman 15 and 50% Unitika 4.
[0053] Samples 8,13, and 18 all have an overall basis weight of 36
ounces/yd.sup.2 and an overall composition of 50% heat resistant
thermoplastic binder material. The core layer 12 has a basis weight
of 24 ounces/yd.sup.2 and a fiber blend of 25% Wellman 6, 25%
Wellman 15, and 50% Unitika 4. The stiffening layers 14 and 16 each
have an overall basis weight of 6 ounces/yd.sup.2 and a fiber blend
of 50% Wellman 6 and 50% Unitika 4.
[0054] Table 4 includes three known previous laminate constructions
identified as Prior 1, Prior 2, and Prior 3. Prior 1 and Prior 2
have an overall basis weight of 52 ounces/yd.sup.2 and an overall
composition that does not include a heat resistant thermoplastic
binder. The core layer of Prior 1 and 2 has a basis weight of 20
ounces/yd.sup.2 and a fiber blend of 80% Martin 3 denier and 20%
Wellman 4.75. The stiffening layers of Prior 1 and Prior 2 each
have a basis weight of 16 ounces/yd.sup.2 and a fiber blend of 65%
chopped fiberglass roving, 28% phenol-formaldehyde thermoset
binder, 4% polyester spunbound scrim, and 3% polyethylene film.
[0055] Prior 3 has an overall basis weight of 38 ounces/yd.sup.2
and an overall composition that does not include any heat resistant
thermoplastic binder material. The core layer for Prior 3 has a
basis weight of 16 ounces/yd.sup.2 and a fiber blend of 44% Wellman
15 and 56% BF Goodrich. The stiffening layers of Prior 3 each have
a basis weight of 11 ounces/yd.sup.2 and a fiber blend of 54%
chopped fiberglass roving, 38% phenol-formaldehyde thermoset
binder, 5% polyester spunbond scrim, and 3% polyethylene film.
[0056] Table 4 compares the sag properties of these various known
laminate constructions and laminate constructions according to the
invention. Table 4 shows that for a given thickness, an increase in
the heat resistant thermoplastic binder percentage will result in a
decrease in the sag as tested. In other words, for a given
thickness, as the binder material percentages increase, the
laminate better resists sagging. Table 4 also shows that increased
basis weight also provides increased resistance to sagging. As seen
in table 4, one advantage of the invention is that for
approximately equal basis weights, a laminate made according to the
invention has significantly better sag resistance at a thickness
less than previous laminate constructions. The ability of the
invention to provide superior sag resistance at an equal basis
weight but at a reduced thickness is advantageous over prior
laminate constructions in that no structural rigidity is sacrificed
but increased headroom is gained.
[0057] Table 5 illustrates the relative sound absorption
characteristics of a composite laminate made according to the
invention as compared to the sound absorption characteristics of
the individual layers forming the composite. The laminate used in
Table 5 has an overall thickness of 0.65 inches with a basis weight
of 24 oz/yd.sup.2. The laminate comprises a core layer sandwiched
between outer layers. The fiber composition of the core layer
comprises: 35% of 0.9 denier fibers, 25% of 3 denier fibers, and
40% of 15 denier fibers; resulting in a basis weight of 12
oz/yd.sup.2 and a thickness of 0.35 inches. The fiber composition
of each outer layer comprises: 50% of 3 denier fibers and 50% of 15
denier fibers; resulting in a basis weight of 6 oz/yd.sup.2 and a
thickness of 0.15 inches.
5TABLE 5 Comparison of Sound Absorption Between the Composite of
the Invention and the individual Layers. [t5] Weight Thickness ASTM
C423 Reverberation Room Sound Absorption in % Layer (oz/yd.sup.2)
(inch) 250 Hz 500 Hz 1000 Hz 2000 Hz 4000 Hz Composite 24 0.65 22
54 80 90 90 Outer 6 0.15 2 7 13 18 32 Core 12 0.35 4 12 31 54 73
Outer 6 0.15 2 7 13 18 32
[0058] The core layer alone absorbs a much greater percentage of
sound at all frequencies than the outer layers. In most cases, the
core layer absorbs at least twice as much as the outer layers. The
superior sound absorbing characteristics of the core layer over the
outer layers is believed to be attributable to the use of the fine
denier fibers in the core layer and the greater thickness of the
core layer.
[0059] The composite has superior sound absorbing characteristics
over all of the individual layers. The improved sound absorbing
characteristics are believed to be mainly related to the increased
thickness of the composite as compared to the individual
layers.
[0060] The comparison of the sound absorbing characteristics
between the composite and the individual layers highlights two
guiding principles regarding sound absorption: the finer the fiber
size, the better the sound absorbing characteristics, and the
thicker the layer, the better the sound absorbing characteristics.
These are general characteristics which do not hold under all
situations.
[0061] The sound absorption property of a material is a direct
function of resistivity, which is itself a function of the
thickness of the layer and the total fiber surface area of the
layer. In general, sound absorption increases as the resistivity
increases--at least up to a point. The total fiber surface area is
related to the relative proportion of fiber sizes in a given layer.
All things being equal, the smaller the fiber size, the greater the
total fiber surface area. Since most layers contain a mixture of
different size fibers, the greater the percentage of fine fiber
will generally yield greater sound absorption.
[0062] There is a point where the material is so resistant to the
passage of sound waves that more sound is reflected than absorbed
in response to further increases in the thickness or total fiber
surface area. To understand this consequence, the resistivity can
be thought of as increasing the average distance that a sound wave
must traverse to pass through the layer. Both the thickness and
total fiber surface area impact the average distance. The thinner
the layer, the shorter will be the average distance through the
layer. The greater the total fiber surface area, the more a
particular sound wave will have to reflect from fiber to fiber to
pass through the layer since it is less likely that a direct path
exists. As the total fiber surface area increases, generally so
does the number of fibers. At some point, the increased number of
fibers will eliminate most of the interstitial spaces between the
fibers and reduce or eliminate paths through the layer. At such
time, the layer reflects more sound than is absorbed, reducing the
sound absorption characteristics.
[0063] Another way to think of the effect of the increasing total
fiber surface area is that in most cases it generally results in an
increase of the density for the layer. At some point, the density
will be great enough that the layer starts behaving more like a
solid and starts reflecting sound.
[0064] While increasing the density of the layer ultimately
negatively impacts sound absorption, in general, increasing the
density will increase the stiffness or bending resistance of the
layer, which helps to prevent sag. As shown in Table 4, in general,
stiffness or bending resistance increases as the percentage of
binder fiber increases. Generally, most binder fibers are not fine
denier. Thus, increased rigidity, whether obtained by greater
density, increased binder fibers, or both, can compromise the sound
absorbing characteristics of the layer.
[0065] The laminate according to the invention applies these
principals in a unique structure to obtain a laminate that is
relatively lightweight and then, but still has the desired sound
absorbing characteristics and strength required for a headliner.
The invention uses an I-beam configuration having a generally
three-layer structure. The outer layers are flexurally stiffer than
the core layer, even though the core layer is generally thicker
than the outer layers. The greater stiffness of the outer layers is
attributable to their greater density and/or their greater
percentage of binder fibers.
[0066] The relatively thin and stiff outer layers connected by the
core layer forms a cross section that better resists bending than a
laminate made solely from outer layer material or the core layer
material, much like an I-beam or a box-beam construction.
[0067] The core layer, however, has better sound absorbing
characteristics than the outer layers, which is attributable to the
use of fine denier fibers and/or greater thickness. The selection
of materials for the outer layers cannot ignore the sound absorbing
properties since the sound must pass through as least one of the
outer layers to reach the core layer.
[0068] It is within the scope of the invention for the core and
outer layers to contain the same type of fibers, but not to the
detriment of the respective predominate functions provided by the
core layer and the outer layers. Care must be taken to make sure
that the fiber mix, i.e. the percentage of each type of fiber in
the layer, in either the core and outer layers does not impair the
primary sound absorbing function of the core layer or the primary
strength function of the outer layer.
[0069] The laminate according to the invention maintains the
necessary balance between overall laminate thickness, sound
absorption performance, and flexural stiffness by selecting the
fiber mix such that the outer layers are generally more dense that
the core layer and/or the core layer has a greater resistivity than
the outer layers.
[0070] More specifically, it is preferred that the core layer
include at least 25% of fine fibers in order that the laminate have
suitable sound absorbing characteristics. The outer layers should
not include more than 20% fine fibers.
[0071] The limits on the fiber mix for the core and outer layers is
constrained by the functional requirements of each of the layers. A
greater percentage of binder fibers leads to greater flexural
stiffness, for a given weight and thickness of the laminate, and
coarser binder fibers result in greater stiffness. Thus, another
way in which to quantify the limits on the fiber mix of the core
and outer layers is that to obtain the desired mix of sound
absorption and flexural stiffness, the percentage of fine fibers in
an outer layer should not be more than half the percentage of fine
fibers in the core layer, up to a maximum of 20% fine fibers in the
outer layer.
[0072] While particular embodiments of the invention have been
shown, it will be understood that the invention is not limited
thereto since modifications may be made by those skilled in the
art, particularly in light of the foregoing teachings. Reasonable
variation and modification are possible within the scope of the
foregoing disclosure of the invention without departing from the
spirit of the invention.
* * * * *